An issue that faces individuals investing for retirement is

An issue that faces individuals investing for retirement is allocating assets around different investment choices. Suppose a study conducted 10 years ago showed that 67% of investors preferred stocks to real estate as an investment. In a recent sample of 800 investors, 304 preferred real estate to stocks (equivalently, 496 preferred stocks to real estate). Is this new data sufficient to conclude that the proportion of investors preferring stocks to real estate has declined from 10 years ago? Conduct the analysis at the .02 level of signifcance.
*I would like to know how to find the test statistic (z) using the formula and not a calculator.

Solution